Vehicles (automobiles, tanks, airplanes, boats, etc.) typically possess fuel tanks in which liquid fuel is free to move, or ‘slosh’, often resulting in a build up of static charge and an accompanying risk of ignition and subsequent explosion. Additionally, both liquid and gaseous fuel can escape unimpeded from conventional fuel tanks in the event of an accidental or intentional penetration of the tank. The risk of explosion and rapidly spreading flames resulting from either of these factors pose serious threats to the vehicle, vehicle occupants, and people or structures in the area.
In the case of liquid fuels, baffles comprising open cellular foams have been used extensively in the aircraft and racing industries to mitigate the effects of liquid fuel sloshing and leakage. One form of baffle, for example, comprises an open cellular plastic foam, such as SafeCrest® foam, available from Crest Foam Industries, Inc. Moonachie, N.J., USA. Such foams are generally applied inside of the fuel tank after construction via cut and placement, post placement expansion (see for example, U.S. Pat. No. 4,764,408) or spray foam application (see for example, www.crestfoam.com). The advantages of such foams include reduced fuel spillage and reduced atomization that results from fuel being trapped inside of the foam cells in case of a tank perforation. As a result, such fuel tank systems mitigate fireball occurrence.
The plastic foam baffles tend to chemically degrade over time, and the debris generated can plug fuel filter systems. The foam baffles also complicate fueling procedures as the fuel tends to foam on contact with the baffle system, thus limiting fueling rates. Debris may also build up and block the foam, thereby reducing fuel tank volume. Furthermore, while plastic foam baffle systems help mitigate spillage in the case of a tank penetration, these foams provide little to no structural reinforcement and therefore do not inhibit the penetration itself. Finally, they are neither thermally nor electrically conductive, and therefore cannot dissipate static charge or heat.
U.S. Pat. No. 4,844,974 describes electrically conductive, chemically resistant carbonaceous fibers which, when packed within a fluid storage vessel, prevent sloshing of the fluid and dissipate static electricity buildup. These fibers further serve to absorb liquid fuels, thereby reducing their mobility and slowing their combustion. While inhibiting flame spread and explosion, the materials of U.S. Pat. No. 4,844,974 provide minimal structural reinforcement, and therefore do not enhance resistance of the storage container to puncture.